Grommets through which control cables are inserted have been known (see, e.g., Patent Literature (hereinafter, referred to “PTL”) 1). Such a grommet is provided with a seal portion that seals against moisture such as rain water at an inner wall of an insertion hole. However, when protruding portions to be provided at the seal portion for the purpose of making insertion of a control cable easier are placed at intervals, there may be a case where the shape of the seal portion cannot conform to a curve shape of the control cable when the control cable curves and a gap is generated between the control cable and the protruding portions, causing a decrease in seal efficiency.